1. Field of the Invention
The invention relates to a three-dimensional imaging device including a pair of left and right image capturing units and a three-dimensional imaging method, more particularly to a technology for correcting any displacement between two images respectively captured for left and right eyes by the image capturing units caused by a shift between optical axes of the image capturing units, thereby ensuring simultaneity of the images.
2. Description of the Related Art
According to two-eye stereoscopic cameras so far disclosed, an image of a target object to be imaged is captured by a pair of left and right image capturing units to obtain a three-dimensional image from the captured left and right images. Conventionally, it is unavoidable that optical axes of a pair of left and right image capturing units are shifted horizontally and vertically relative to each other. This invention focuses on the vertical shift between the optical axes. To conventionally correct any vertical displacement between images respectively captured for left and right eyes due to such a vertical shift between the optical axes, the displacement is detected, and feedback of the detected displacement is transmitted to a mechanical drive unit provided in a multi-axial camera platform to adjust angles of depression and angles of elevation of the image capturing units respectively capturing the right-eye and lefty-eye images, thereby correcting the displacement. This technique mechanically corrects the displacement (for example, see the Patent Reference 1).
In some conventional cameras, image capturing units are each embedded with a variable power lens constituting a zoom lens so that a magnifying power is variable. In these cameras, any vertical displacement between the left-eye image and the right-eye image is increased by an error between different magnifying powers of the variable power lenses. To correct the displacement between the two images due to such an error, the generated displacement is detected, and feedback of the detected displacement is transmitted to a variable power lens drive mechanism so that the error is cancelled. This technique too mechanically corrects the displacement. (for example, see the Patent Reference 2).